The h Bar - 2020-11-25

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2:02 AM

"financial engineering" involves more than just making money, it also involves insurance-like concepts such as hedging. in other words, "not losing money." yes there is no such thing as a free lunch. reliability/ fault tolerance/ stability is a crosscutting goal across all engineering fields and there are many parallels in financial engineering. the field has a concept "stress testing" not unlike engineering that played a big role in 2008 crash when govt adopted it as official policy.

one of the most successful financial engineers/ quants of all time: jim simons a billionaire, a phd mathematician.

2:35 AM

@vzn But it's not engineering in the way people typically associate with the term. If you practice social engineering, you don't call yourself an engineer. If you practice financial engineering, you don't call yourself an engineer. You might call yourself a "financial engineer"; but that distinction can be huge and it seems like a buzzword. By the sounds of it Jim Simons couldn't advertise himself as just an "engineer" in Canada, for example.

3:03 AM

allo... I'm under the impression there is a reference to the Lagrange points of Jupiter-Europa in the movie 2010: Odyssey 2. Like... one of the monolith is located at a Lagrange point for the Jupiter-Europa system but I can't find anywhere to confirm this.

@BioPhysicist It's a pity. It's one of three topics in life about which you will never know enough.

#2 is series expansions (of all types).

... and we can't discuss #1 in this forum.

3:22 AM

JM not in the mood to argue. looks like this wikipedia pg needs a lot of revision acc to you. as they say in NYC, good luck with that!

Financial engineering

Financial engineering is a multidisciplinary field involving financial theory, methods of engineering, tools of mathematics and the practice of programming. It has also been defined as the application of technical methods, especially from mathematical finance and computational finance, in the practice of finance.Financial engineering draws on tools from applied mathematics, computer science, statistics and economic theory. In the broadest sense, anyone who uses technical tools in finance could be called a financial engineer, for example any computer programmer in a bank or any statistician in a...

I have a lot of bias against the whole financial industry in general due to my more ancom like alignment and how a lot of multinationals used that industry to cause a mess in many places particularly the environment. But all of that aside, JMac is correct that finance is not as stable as natural science, because insurance and transactions in general are highly sensitive to political and cultural influences, both of these do not follow stochastic

equations strictly and are highly adaptive complex systems

Financial engineering and econophysics are indeed relatively young fields

but I don't know how they are recognised among the natural sciences

I found some of econophysics ideas useful, as capital kinda has its own thermodynamic like system

but unlike thermodynamics, capital can be "created from thin air" due to the time value of money

so you have something else instead of the usual 1st and 2nd law

am a strong critic of "financialization" of the economy myself for many yrs and other aspects of financial engineering. there is a particular economist mike hudson that writes excellent/ erudite critique along these lines & hes undeservedly obscure.

economics was branded the dismal science decades ago for a reason... that has not gone away in the interim...

@Secret that is actually one of the great misnomers of economics. "everything has a price"

yeah, time value of money is technically only an approximation. What really happens is that every economy is supported by the exchange and distribution of natural resources

@skullpatrol esp politicians! :P

financial capitalism ignores that and hence the growing divide between the two costed the environment

3:29 AM

@vzn Truth.

this is easily seen from the proliferation of derivatives

derivatives have been called WMD by buffet iirc....!

user486313

hi there

You can also see how quick the system squeeches to a halt back in early COVID-19, when trade is effectively halted by the lockdowns

though it quickly adapted

@user131585 hi, and welcome

3:32 AM

COVID-19 is bringing world capitalism to its knees. or maybe its unrestricted capitalism bringing the world to its knees.

user486313

@Secret I work at a Starbucks, while in academia for the time being. Doing interesting research. Have no money, feel the poverty, am smart, live in a great city but can't buy anything but pay rent and get food. So, I feel to all those finance bros ... let them do their thing and enjoy. What's the alternative? Someone like me, with no money for anything.

user486313

I don't see a middle class / middle ground, economically, I think ...

what research are you doing?

user486313

So I no longer hate / despise / think lowly of finance people ... I say ... good for them for having good salaries and bonuses ...

user486313

@vzn fluid dynamics, broadly speaking :)

3:35 AM

have you chosen your phd yet?

user486313

if there's a middle class / middle ground to aim for, I would love to know what that is ...

iirc :-)

user486313

@skullpatrol yeah :)

user486313

@skullpatrol are you a professor?

coolio

user486313

3:39 AM

@Secret I am clearly "overqualified" for my role as a barista at Starbucks.

user486313

Want to know who I work with? It's sad ...

user486313

ex-cons, going in and out of prison terms ...

user486313

with me a few months, and gone for the next 3 years ...

user486313

for something stupid, as a product of their environment ...

user486313

I no longer fault finance bros for doing what they do, for money ...

user486313

3:40 AM

The alternative is horrific, I think ...

user486313

I've now seen it firsthand ...

@user131585 !!! srsly? me too! what are you studying about fluids? do you have a degree? what country?

user486313

@vzn how a wing moves in air or water, for example -- maybe in a turbulent flow?

user486313

United States

user486313

^ how it moves, either passively or optimized / controlled

user486313

3:47 AM

@vzn the thing with that is: many people are doing this now

user486313

especially with machine learning

user486313

and so, I feel I am not distinguishing myself, by competing in such a hot area perhaps

@user131585 am always on the vigilant lookout for anyone interested in fluids....

@user131585 in some ways hot, in some ways not! what do you think are indicators its a "hot field"?

user486313

I feel I should look where others aren't looking, and if in that relatively unexplored area of fluids or whatever, I can somehow convince people that it's important and they should pay attention to it, then I'd like to write a few, foundational papers in this area ...

a rare ambition in some ways, not in others!

user486313

3:49 AM

... emulating one of my mentors basically -- he essentially founded a new subfield a few decades ago, and much of his work is used today by modern researchers ...

and who is that?

user486313

hot because all the figures that you are asking the important questions to, they already have some results to share with you ...

user486313

unpublished but shareable ... people won't catch up ...

researchers always have stuff to share, unpublished...

user486313

yeah ...

user486313

3:51 AM

I am amazed by their generosity, but mostly I think they feel safe and far enough ahead ...

sometimes science is a competition, sometimes a collaboration...

user486313

my mentor, who's work appeared regularly in Science and Nature, had many tens of thousands of citations ... and was front and center for the NSF in terms of funding ... told me that he basically wrote his foundational papers ... without knowing whether they would ever be successful ...

user486313

impossible to predict ...

user486313

he just knew the area was unexplored, and he felt people could / should pay attention to it ...

user486313

and he moved in that direction ...

3:53 AM

seems there is no reason not to name him...?

user486313

eh, I rather not ... sorry ...

user486313

I'm happy to share stories, though ...

user486313

and wisdom / lessons learned by him ...

launching a research area is a elite privilege afforded to a few...

how did you meet?

user486313

yes, his family is quite distinguished -- I would say that ...

user486313

3:55 AM

so perhaps he did have some head start ...

user486313

he knows my advisor quite well ...

ok, this is verging more on storytelling than chatting at this point :P

user486313

yeah :)

user486313

I'm sleeping soon ...

user486313

@vzn where are you in the world?

user486313

3:57 AM

are you in college? PhD?

US BS software engr

user486313

Nice!

user486313

do you like CFD coding?

see your msg inbox drop by the other room for more info/ discussion sometime :)

user486313

ok, will do

3:59 AM

want to get into CFD and was starting a prj with another individual recently until he disappeared :(

user486313

disappeared?

am very excited by the improved simulation software think new vistas will be opening up shortly, but seems very few are alert/ cognizant of the possibilities at this stage.

user486313

as in ... he died?

user486313

I see

@user131585 lol we started a (meaningful! promising!) prj in chat & he didnt return. dont think he died :) ... alas the nature of chat. its called the hbar for a reason...

user486313

4:01 AM

I wonder about how detailed a simulation I like ... I think Direct Numerical Simulations (DNS) are unnecessarily difficult ... but I'm not 100% sure ...

user486313

Ah, I see haha

(arg was trying to multitask my ipad and then the keyboard stopped working on this window, @#%& dumb glitches.)

user486313

g'nite @vzn :)

user486313

sorry to hear :(

yikes just when it started getting interesting o_O 131

user486313

4:04 AM

do you like experiments in a lab?

user486313

say, experiments to match simulations

user486313

or, do you like pure computations / simulations?

user486313

for example, my friend is doing pure computations at Columbia Applied Math

user486313

tsunami modeling, I think ... or something related ...

did quite a few standard physics experiments as undergrad. have been working on computational "experiments" heavily/ copiously over ½ decade now, will introduce you sometime if you dont disappear also :) there is some loose connection to physics but its generally more abstract. it does seem to relate to dynamical systems a lot more lately.

user486313

4:05 AM

I might be busy starting a new subfield in fluid dynamics soon ;)

user486313

if it takes off, I won't be back on Stack Exchange until maybe retirement age ...

@user131585 what subfield?

user486313

can't say, for now ;)

lol ok dude

← gonna be lead singer of a rock band o_O

user486313

haha ... that'd be nice

user486313

4:08 AM

are you at a strong school for CS / engineering?

user486313

who's @JohnRennie and @skullpatrol? are they like moderators here or something?

middle-tier school with decent CS + engr at the time.

user486313

I see

JR is close to a mod. skullpatrol is a mysterious/ elusive somebody who has been around many yrs. secret is also an oldtimer.

user486313

I see

4:11 AM

have you heard of Yitang Zhang? you might find his story inspirational :)

(oh, bye)

4:33 AM

@Secret there is a lot to challenge here but googling you might start with this The Illegal Actions of the Federal Reserve: An Analysis of How the Nation's Central Bank Has Acted Outside the Law in Responding to the Current Financial Crisis / Emerson scholarship.law.wm.edu/cgi/…

4:49 AM

I searched for proof that torque=Ialpha can be applied from fixed axis, centroidal axis of instantaneous axis of rotation but got shit results is there any proper keyword?

5:45 AM

Did anyone here said, Comtupar Science Engynar!!?

@user131585 I'm not a moderator, just a user who has been around for so long they've become part of the furniture.

6:13 AM

Hi All....

Hi @JohnRennie Sir. No question for now. I am reading Griffith Electrodynamics it is amazing book.

@JohnRennie which college were you in?

@NiharKarve I did my BA at Peterhouse then switched to Jesus to do my PhD

@JohnRennie Where's Jesus College? My mental map is only decent for the "main" road

At the north end of the city centre

I see

6:25 AM

Here

please don't be offended that I called the road with King's the main one :)

:-)

Peterhouse is on Trumpington street as well

user image

Some lesser known facts about Sherlock Holmes

Method of Loci

6:40 AM

@JohnRennie I seem to recall making a rather loud wisecrack about the street name

As in trump being a euphemism for fart? :-)

if only it were that polite :)

When we you at Cambridge?

I didn't study there (not yet, at least!), but I did pop over for a visit some time in 2018

I loved Cambridge. I spent six years there during my two degrees and really enjoyed it.

6:59 AM

I thought it looked really nice too - in Cambridge vs. Oxford, I would choose to go to Cambridge in a heartbeat

7:32 AM

⁽ⁿᵒᵗʰᶦⁿᵍ ᵃᵍᵃᶦⁿˢᵗ ᴼˣᶠᵒʳᵈ⁾

1 hour later…

8:51 AM

user image

My goodness, you take a day off from going through the review queues and the close queue explodes :-(

9:04 AM

Er, what's going on with physics.stackexchange.com/questions/595789? Isn't it off-topic?

@NiharKarve we get lots of homework questions. I've voted to close it, but it takes five close votes to close a question. Hopefully other users will be along to vote to close it soon.

Do you use the method of loci, sir? @JohnRennie

I don't even know what that is :-)

3 hours ago, by RewCie

Some lesser known facts about Sherlock Holmes

I guess not, then :-)

@JohnRennie ah, I wasn't aware that it took 5 of them

4 hours later…

12:50 PM

@Slereah another round

thx

Maybe I should indeed get back into looking for it

It hasn't been a great year for job searches

Some come out via this, has a list of all recent ones sent out there too

1:38 PM

:56251406 Well that was probably the rudest possible way to say that, especially since you basically called me out without pinging me... But I'd love to hear how it "doesn't align with reality" to suggest that most people don't actually consider "financial engineering" as an actual type of engineering. This isn't something I pulled out of my ass, practically everything on "financial engineering" points this out, including the Wikipedia page you link.

2:34 PM

I am facing problem in complex number and not able to identify where I am confusing myself and where I am not able to understand it is there any way to to pick up of where you are lacking knowledge

2:49 PM

Hey @Charlie, where'd you get your sweet, sweet profile picture

google images

@PrateekMourya You can try googling for lecture notes written on complex number for physicists?

wow, I haven't played runescape in ages

60% of people who looked like that were macroing

it's the default skin so they probably were

3:50 PM

I am not physicist

I am preparing for engineering entrance exam in india called jee and a high school student

Hmm, what problem are you facing exactly?

4:12 PM

0

Q: Reward closed question

I was thinking on add a reward to this question (not asked by me): Two blocks are placed side by side on a surface (friction is present). What is the frictional force distribution between two blocks? because currently it has four answers, that can be grouped in two answers supporting an idea (uni...

4:33 PM

thanks @JMac, I was just starting to write an answer but upvoting yours is much easier ;)

Haha no problem. I got in the zone quick on that one.

5:07 PM

@NiharKarve that is my question

To myself

Oh sorry, I hadn't read your message properly :)

Maybe try solving problems that deal with a specific aspect of complex numbers to see where you're a bit confused?

Hey! Consider a semi-Riemannian manifold $\zeta^{2,2}$ with metric, $g=\frac{dxdy}{xy}+\frac{dudv}{v-uv}.$ How could you define a 3-dimensional slice of $\zeta^{2,2}$? Does there exist a foliation of $\zeta^{2,2}$ using leaves of dimension 2?

5:30 PM

@ACuriousMind "during vacuum pair production, the virtual electron will be attracted to the nucleus while the virtual positron will be repelled" - BS-meter?

@ACuriousMind regarding your comment under JMac's answer, is the functionality in question actually available to us, or do we still need to wait?

@NiharKarve the readings are off the charts :P

if it is, then we should probably start a new thread on meta

just so everybody's on board with the new text

@EmilioPisanty Everything in the mod tools looks as if it's actually available

do you really think we should renegotiate the text and not just make it so that the current text is visible to all users in a first step?

@ACuriousMind good point. probably not, at least as a first step.

maybe you can implement the change, and then make a thread on meta announcing it, and if anyone has changes to propose they can post them as an answer

5:45 PM

@EmilioPisanty I'll wait for feedback from my fellow mods, but that sounds good to me

How often are the mod elections?

@NiharKarve there's no fixed schedule, we have an election whenever the current mods feel they need more help (or plan to step down and want a replacement)

user486313

@skullpatrol You're so helpful; thank you for everything that you do ...

3

I see

6:13 PM

Unless we stage a rebellion and rise up against the current mods

I assume the equivalent of "marching on the capital" would be some kind of baseball-bat-based attack on some of the stackexchange server hardware

I actually came to ask a question so I retract my earlier statements about overthrowing the authorities

In the derivation of Noether's theorem we derive information about conserved quantities by using the assumption that an arbitrary change in the Lagrangian, $\delta \mathcal L$, must be equal to the time derivative of some function $dF/dt$, which seems to imply that the only changes to the Lagrangian that leave the stationary points of the action invariant are those that are equivalent to the addition of some $dF/dt$, is this the case? I looked around a bit on the site and couldn't really find

an answer

About that, both dmckee and David Z stepped down this year

So it's not impossible that we see one next year

@Charlie I've heard the worst damage you can inflict is to ask about a specific user suspension, twice

6:55 PM

@ACuriousMind maybe it's worth checking with the dev team before making a new close-reason. Maybe the existing ones can be edited to fill out the rest of the slots?

if nothing else, having a fragmented history with multiple database IDs ends up making it hard to analyze the history from SEDE

7:15 PM

made my first Physics Q&A in a long long time:

0

Q: Error in an argument for classical transverse Doppler effect

I was recently reviewing the classical Doppler effect for intro physics students. One aspect of such is that there's no transverse effect: An observer moving perpendicular to the motion of a plane wave will register no change in frequency. However, my first attempt to construct the argument ran i...

waves acoustics galilean-relativity phase-velocity

3 hours later…

10:15 PM

@user131585 you are most welcome

user486313

@JohnRennie my interests are more pure science, pure-applied math, with a specific set of journals in mind to write for. however, my mentor / advisor is more like applied-applied, rather than pure-applied, and writes for IEEE type journals in robotics, controls, data-driven stuffs. what should I do then?

user486313

@JohnRennie I love mathematics, and a bit of engineering and science, and coding. Matching models and simulations with experiments. But elegant stuffs, not crazy sophisticated robotics gotten from a $5 million dollar 3-year NSF grant, for example.

user486313

elegant in the sense that the phenomena have little-to-no feedback control ... and yet is stable ... because of some surprising mechanism, for example ...

@user131585 what journals do you want to write for? what are you coding?

@Charlie lol very funny, they have too much power for that :P

user486313

@vzn Journal of Fluid Mechanics, for example

user486313

10:28 PM

Journal of Computational Physics, maybe

awesome! :)

user486313

What about you?

user486313

any ideas, so far?

user486313

would you go more IEEE @vzn?

user486313

I seem to have qualms about doing so ...

user486313

10:30 PM

my heart isn't so much into controls and optimization ...

@user131585 publishing anywhere is great :) ... a few around here do it but its a minority.

user486313

I see

@user131585 ideas about what? where to publish?

user486313

yeah

user486313

your tastes, basically -- whom to write for

user486313

10:31 PM

what's your audience

@user131585 have a blog, have been writing for yrs, have some published work. my audience is anyone who will listen :P

@user131585 was looking up DNS last nite after you mentioned it, very intriguing! :)

user486313

I see :)

user486313

@vzn yes

Direct numerical simulation

A direct numerical simulation (DNS) is a simulation in computational fluid dynamics in which the Navier–Stokes equations are numerically solved without any turbulence model. This means that the whole range of spatial and temporal scales of the turbulence must be resolved. All the spatial scales of the turbulence must be resolved in the computational mesh, from the smallest dissipative scales (Kolmogorov microscales), up to the integral scale L {\displaystyle L} , associated with the motions containing most of the kinetic energy. The Kolmogorov scale,...

what do you know about it, is someone you know working on it, what are they doing with it?

user486313

I'm not sure that DNS suits me ... I maybe prefer close-enough approximations to experiments, not super-detailed DNS that may border on being intractable.

user486313

10:34 PM

their papers have DNS + experiments, but they're like a leader in their field, so they can do both ...

yes was noticing that immediately about it, the computational complexity is mentioned several times in the wikipedia article.

user486313

they regularly publish in JFM, for example

user486313

yeah ...

can you plz cite some of this stuff?

user486313

thing is: the extra detail you get from all the extra work ... may not give you any more insight, once you have a good enough approximation via another numerical method / simulation that matches an experiment well

10:36 PM

have you worked with fluid/ physics modelling software? have you done some experiments? are you a student?

user486313

yeah ... a bit of both

lol am listening!

user486313

yes

user486313

I'm starting my own subfield soon ;)

user486313

and will disappear from Stack Exchange to make it happen ...

user486313

10:38 PM

you should start your own, too ...

no need to disappear... sounds kind of drastic to me :P

lol have started a few paradigm shifts + revolutions in my time but they shall remain nameless like you :P

user486313

that requires looking into an area that no one else is really looking at, and working on ...

user486313

haha, I see ...

user486313

@vzn could I make a suggestion ... ?

user486313

re: your blog, for example

user486313

10:39 PM

I haven't read it, just FYI

user486313

Hi @RichardMyers

← amused at the starbucks barista targeting fluid dynamics research :P

user486313

@vzn yeah :)

user486313

do you have a job too?

@user131585 yes software engr. pays the bills. sometimes advanced, sometimes mundane.

user486313

10:48 PM

I see

user486313

@vzn I know ... 3 software engineers?

user486313

all good friends

user486313

all make much more money than me ...

user486313

and write basic if/else statements all day, everyday ...

user486313

they like the stability; I'm more the dreamer ...

user486313

10:49 PM

so I live in poverty for the time being ...

user486313

it's a choice, ya know?

lol software engr is way more hardcore than that esp senior level, sometimes the coding is the easy part so t speak.

user486313

I see haha ...

@user131585 alas, inequality/ mobility is less of a choice than it used to be... at least in US. can you name your country?

user486313

U.S. :)

10:51 PM

ok what state?

user486313

yeah, for someone born into a ghetto, into institutionalized racist structures, the poverty may not be a choice, so that's a good point ...

user486313

rather not tell :)

@ZeroTheHero did you hear the news? are you alluding to this? Theories abound over mystery metal monolith found in Utah theguardian.com/us-news/2020/nov/24/…

user486313

have to stay in my dungeon and start my new subfield in fluid dynamics first :)

@user131585 East/ MidEast/ Midwest/ West?

@user131585 did you have an idea about which subfield? why fluids anyway? still trying to follow. theres mystery, and vagueness.

user486313

10:53 PM

one of those 4, I think :)

user486313

you're in ... the Midwest, I'd guess ...

user486313

middle-tier, CS / engineering schools are all there, it seems

@user131585 lol will trade info for info :P

user486313

I love the Midwest very much

user486313

haha ...

user486313

10:54 PM

tense negotiations in the h bar ...

@user131585 my point was more that capitalism as now practiced in US, and spread elsewhere, is somewhat universally crushing in various senses. (aka neoliberalism)

user486313

why fluids? mentors, mostly ... then I followed ... and fell in love ...

ok cool, mentors are awesome, a (sometimes rare) treasure, something to treasure

not many ppl "fall in love" with science... kind of an oxymoron. but can relate! :)

user486313

what various senses?

user486313

yeah :)

10:58 PM

its a long story re capitalism, but basically its turned into a kind of hypercapitalism that is not the same as the prior generation. this has spanned decades, roughly ½ century now.

user486313

I see

user486313

would you, for example, be opposed to a new Starbucks in your area, taking up an old mom and pop coffee shop?

that is exactly the kind of quandary that is an everyday question.

user486313

here in my neighborhood, those fights are pretty fierce ...

user486313

many, many town hall meetings, protests, before Starbucks finally still gets their way ...

11:00 PM

mom & pop shops are an uphill battle for generations now. there are many forces lined up/ pushing against them.

in some ways "democracy" is just an illusion.

some/ others might say, in many ways.

user486313

yeah, I hear ya ...

user486313

@vzn have to go for now, but I wanted to suggest that you think about your audience a bit

user486313

you have time, so no rush ...

user486313

figure out who you want to write for, if you want to publish, that is ...

@user131585 ok... think what about my audience?

user486313

11:09 PM

is your audience from science or engineering, for example

user486313

a bit in between? pure science? robotics?

user486313

knowing that is important

@user131585 in some ways its a broad audience :) in other ways theres no audience :'(

user486313

editors at the good journals advise this, as general advice for publishing ...

user486313

know your audience first ...

11:11 PM

@user131585 blogging is a kind of publishing. have published elsewhere. yes you have good advice about research publishing.

user486313

if you blog, then sure -- you can write for anyone who wants to visit your blog and read

user486313

yes, exactly

user486313

not sure what your aim is, after undergrad

@user131585 have some similar aims as you. they are mostly laid out in the blog.

user486313

I see -- nice

user486313

11:12 PM

blogging is perhaps not so effective in communicating science to others ...

user486313

not sure though ...

user486313

just my own feelings, and based on feedback I get from writers, lawyers, etc.

@user131585 it is partly an open question how to effectively communicate science :) o_O

user486313

true true ...

user486313

gonna get a blueberry pie now, since @SirCumference is here ...

user486313

11:14 PM

bye @vzn, dinner time

user486313

talk later

bye

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